Conductors and Insulators

Conductors are materials that allow electric charges, especially electrons, to flow freely through them. This ability to allow the free movement of electrons makes them essential for carrying electric current.

Examples of conductors

• Copper
• Silver
• Gold
• Steel
• Iron

Key point

Conductors are used in electrical circuits and wiring because they are efficient at carrying electrical charges.

Properties of conductors

1. Presence of Free Electrons; Conductors have many free electrons that can move easily from one atom to another. These free electrons make conductors good at allowing electric current to pass through.
2. High Electrical Conductivity; Conductors allow electric charges to flow through them easily, making them very efficient in carrying current.
3. Good Heat Conductors; Most conductors of electricity are also good conductors of heat. This is why metals feel cold to the touch—they absorb heat quickly.
4. Low Resistivity; Conductors have low electrical resistance, which means they do not oppose the flow of current significantly.
5. Used to Carry Current; Because they allow current to pass freely, conductors are used in wires, cables, and all electrical and electronic components.
6. Spread of Electric Charge; When charged, conductors distribute the electric charge over their surface because the free electrons repel each other and move apart.

Examples; Common conductors include copper, silver, aluminum, gold, and iron.

Applications of conductors

1. Electrical Wiring: Copper and aluminum are the most commonly used conductors for electrical wiring because of their high conductivity (the ability to conduct electricity). These metals are used to create power lines, household wiring, and electrical components in appliances and machines.
2. Electronics: In electronic devices like phones, computers, and televisions, conductors like copper and gold are used in circuits and circuit boards to enable the flow of current between different parts of the device.
3. Batteries: Copper is often used as a conductor in battery terminals because it allows electric charge to flow easily between the battery and the device it powers.
4. Lightning Rods: Metal rods (usually copper or aluminum) are used as lightning rods because they can conduct the electrical charge safely from the atmosphere to the ground, protecting buildings from lightning strikes.

Insulators are materials that do not allow electric charges to flow easily through them. In insulators, electrons are tightly bound to their atoms and cannot move freely. This means electric charges remain trapped, making insulators poor conductors of electricity.

Examples of insulators

• Plastic
• Rubber
• Glass
• Wood
• Air (under normal conditions)

Key point

Insulators are commonly used to protect us from electric shocks, such as in the plastic coating on electrical wires.

Properties of insulators

1. No Free Electrons; Insulators do not have free electrons. The electrons are tightly held to the atoms, which means they cannot move freely.
2. Low Electrical Conductivity; Insulators do not allow electric current to pass through them easily. They strongly resist the flow of electricity.
3. Poor Heat Conductors; Insulators generally do not conduct heat well, so they are also used for thermal insulation.
4. High Resistivity; Insulators have high electrical resistance, which means they oppose the flow of electric current significantly.
5. Used to Prevent Electric Shock; Insulators are used as protective coverings on wires and devices to prevent people from coming into contact with live electrical parts.
6. Localized Charge Retention; When charged, insulators tend to keep the electric charge at the spot where it was placed since the charges cannot move through the material.

Examples; Common insulators include plastic, rubber, glass, air, and wood.

Applications of insulators

1. Protecting from Electric Shocks: Plastic, rubber, and glass are used as insulators in the coating of electrical wires. They prevent electric current from leaking out and shocking people who might come in contact with the wire. For instance, the plastic around household wiring ensures that we do not touch live wires and get electrocuted.
2. Household Electrical Appliances: The outer casings of electrical appliances like toasters, hairdryers, and lamps are made from insulating materials like plastic or ceramic to ensure that the electrical components inside are not exposed to external touch, preventing electrical hazards.
3. Insulated Tools: Rubber or plastic-coated tools are used by electricians and engineers to handle live wires safely, as these materials prevent the flow of electricity through the tools into the user.
4. Power Lines: While conductors like copper or aluminum are used in the transmission of power, the power lines are often suspended on insulating materials (like ceramic insulators) to prevent the electricity from escaping and causing short circuits or other hazards.
5. Electromagnetic Devices: Glass or plastic insulators are also used in transformers, capacitors, and other electrical components where it is important to prevent unwanted current flow between conductors within the device.